Process for purifying a gas containing hydrogen sulphide and sulphur dioxide

Abstract

A process for the production of elemental sulphur by reacting hydrogen sulphide with sulphur dioxide in a liquid reaction medium comprising an organic solvent for the two compounds, e.g., ethylene glycol, and containing at least one soluble catalytic basic compound, e.g., sodium salicylate, comprises bringing a gas mixture containing sulphur dioxide and hydrogen sulphide into contact with a co-current of the solvent containing the catalytic basic compound.

What is claimed is: 
     
       1. In a process for the production of elemental sulphur by reacting hydrogen sulphide and sulphur dioxide in a liquid reaction medium comprising an organic solvent, by bringing a gas mixture containing sulphur dioxide and hydrogen sulphide into the presence of at least one catalytic basic compound which is soluble in the solvent, the improvement which comprises passing and reacting the gas mixture and liquid in a co-current mode downwardly through a vertical packed column to obtain sulfur and water. 
     
     
       2. A process according to claim 1, in which the gas mixture brought into contact with the solvent contains hydrogen sulphide and sulphur dioxide in a molar ratio of about 1.5 to about 2.5 moles of hydrogen sulphide per mole of sulphur dioxide. 
     
     
       3. A process according to claim 2, in which the solvent used is selected from the group consisting of ethylene glycol, propylene glycol, a liquid polyethylene glycol and a liquid polypropylene glycol. 
     
     
       4. A process according to claim 3, in which the basic compound used is an ammonium salt, an alkali metal salt or an alkaline-earth metal salt of a carboxylic acid. 
     
     
       5. A process according to claim 3, in which the basic compound used is an ammonium salt, an alkali metal salt of benzoic acid or an alkaline-earth metal salt of salicylic acid. 
     
     
       6. A process according to claim 1, in which the gas mixture brought into contact with the solvent contains hydrogen sulphide and sulphur dioxide in a molar ratio of about 1.9 to about 2.1 moles of hydrogen sulphide per mole of sulphur dioxide. 
     
     
       7. A process according to claim 1, in which the solvent used is selected from the group consisting of ethylene glycol, propylene glycol, a liquid polyethylene glycol and a liquid polypropylene glycol. 
     
     
       8. A process according to claim 7, in which the basic compound used is an ammonium salt, an alkali metal salt or an alkaline-earth metal salt of a carboxylic acid. 
     
     
       9. A process according to claim 7, in which the basic compound used is an ammonium salt, an alkali metal salt of benzoic acid or an alkaline-art meal salt of salicylic acid. 
     
     
       10. A process according to claim 1, in which the basic compound used is an ammonium salt, an alkali metal salt or an alkaline-earth metal salt of a carboxylic acid. 
     
     
       11. A process according to claim 1, in which the basic compound used is an ammonium or alkali metal salt of benzoic acid or an ammonium or alkali metal salt of salicyclic acid. 
     
     
       12. A process according to claim 1, wherein the packing is a random packing. 
     
     
       13. A process according to claim 1, wherein the packing comprises ceramic saddles. 
     
     
       14. A process according to claim 1, further comprising separating the organic solvent at the bottom of the column, passing the separated organic solvent through a heat exchanger to heat the solvent, and recycling the resultant heated organic solvent to the top of the column.